Portable jib-crane.



En. 396.406. G EATENTED AUG. 1s, 190s.

' E. E. MAXEIELD R G. G. GARDNER, JR.

PORTABLE JIR CRANE.

APPLICATION FILED JULY 3l, 1907.

2 SHEETS-SHEET 1.

PATENTED AUG. 1,8, 1908- H. H. MAXFIELD @L G. C. GARDNER', JR.

PORTABLE .TIB CRANE. APPLIOATION FILED JULY a1, 1907.

avm-3.1mm

z SHEETS-SHEET 2.

UNITED STATES PATENT OFFICE.

HOWARD H. MAXFIELD AND GEORGE CLINTON GARDNER, JR., OF TRENTON, NEWJERSEY.

PORTABLE .TIB-CRANE.

To all whom t 'may concern:

Be it known that we, HOWARD H. MAX- FIELD and GEORGE CLINTON GARDNER,Jr., citizens of the United States, and residents of Trenton, in thecounty of Mercer and State of New Jersey, have invented certain new anduseful lm rovements in Portable Jib- Oranes, of whic the following is aspecication.

This invention relates to improvements in portable jib cranes and moreparticularly to that class of such cranes which are employed where therapid unloading and loading of material and the removing of machineparts occurs frequently and great facility in shifting and moving thecrane is desirable without requiring the necessity of guying or bracingthe crane each time it has been shifted and the object of our inventionis to provide a crane of this kind, which is strong and durable andreliable, and easy in action, and by means of which a load can be raisedand lowered or shifted rapidly and which requires no anchorage on theiioor or ground or any guy line or similar brace.

ln the accompanying drawings, in which like characters of referenceindicate like parts in all the iigures: Figure 1 is a side view of ourimproved crane, parts being broken away and others in section. Fig. 2 isan enlarged detail vertical section of the upper parts of the mast orstandard. Fig. 3 is a plan view of the crane, parts being broken out andshown in section. Fig. 4 is an end view of the upper part of the craneparts being broken out and others shown in section, the hoisting cablebeing omitted. Fig. 5 is a sectional plan view of the line 4 4, ofFig.4, parts of the base being broken away.

The entire crane rests and is secured upon a base plate 1 preferablymade circular in shape and of cast iron and of dimensions proportionateto the size of the crane. On this base 1 is erected a standard or mast 2which is composed essentially of three bars 3 preferably made of angleiron, but which can be made of rolled iron or cast metal of any otherdesired shape and which are suitably connected by one or more braces orcross pieces 4 on which for example, the winding gear 5 of any desiredconstruction may be mounted.

Specification of Letters Patent.

Application :filed July 31,

The three bars, or more, forming the standard or mast, are united attheir upper ends by a mast cap or center plate 6, the lower part or neckof which extends downward in the hollow-mast or standard formed by thebars and is securely riveted to the upper ends of said bars by a seriesof rivets 7 so that this mast cap or center plate firmly and securelyunites and binds together the upper ends of the bars forming the mast orstandard. The mast cap 6 is provided with an external annular rib 8, andthe upper end of this inner center plate 6 is surrounded by an annularhousing 9, made of two semi-circular sections bolted together by bolts1() as shown in Figs. 1 and 3. This housing is provided in its innerface with an annular recess 11 for receiving the rib 8 and the rollerbearings 12 and 13 resting respectively against the upper and lowersurfaces of the rib 8 and against the upper and lower surfaces of therecess 11, the rib 8 being wedge shaped and the upper and lower faces ofthe recess 1 1 shaped accordingly so that the rollers 12 and 13 in theshape of a truncated cone can be used. The rollers 12 and 13 take up theentire vertical thrust.

For the purpose of taking up any lateral thrust vertical anti-frictionrollers 14 are mounted in recesses formed in the adjacent vertical facesof the central plate 6 andthe housing 9 beneath the rib 8 as clearlyshown in Fig. 2. Webs 15 of any suitable shape project upward from thetop of the housing 9 as is clearly shown in Fig. 3 and to these webs thechannel bars or other rolled bars 16 are bolted which rolled bars formthe boom of the crane and thus turn with the housing 9 on the centerplate or cap 6.

The boom formed by the bar 16 is provided with a truss rod 17 secured atthe rear or shorter end of the boom to a bolt 18 uniting the two rods 16and at the front end of the boom to an upwardly extending bracket 18 bymeans of an eye and threaded end and nut connection so that the trussrod can be drawn up and tightened when necessary. The truss rod passesover a truss bearing 20 formed with standards bolted to the inner sidesof the beams 16 and on the upper end of this truss bearing a suspensioneye 2 1 is formed for receiving a hook attached to a cable by means ofwhich the entire crane can readily v and is passed over two sheaves 25between which it passes over the sheave 26 of the hoisting hook 27 andthen passes over a sheave 28 on the truss bearing 20 and then' downthrough the center of the mast of the hoisting drum.

The sheaves 25 are mounted on a carriage 29 running on the boom, saidcarriage having flanged wheels 30, the flanges of which extend down onthe inner sides of the beams 16 and the treads of the wheels 30 runningon the upper edges of the beam 16 of the boom so as to preventderailment of the carriage. These wheels are mounted on axles 31 uponwhich they rotate, said axles forming an arbor for the sheaves 25. Asthe boom is balanced and as the vertical and lateral thrust is taken upby the roller bearings, the boom may be freely rotated in any directionand by means of the hoisting drum the load can be brought to any pointwithin the circle described by the length of the radius of the boom. Thecounter-weight 22 suspend ed from`the rear end of the boom a properdistance from the center of the mast in conjunction with the weight ofthe base always maintains the crane in a condition of stable equilibriumwith a load at any point on the boom even when the load is suddenlystarted.

The operation is as follows When the load is to be raised the hoistingcable 23 is Wound on the Winding drum whereby the hoisting hook 27 israised correspondingly. If the load is to be shifted to any point of acircle of a radius extending from the center of the mast to the point ofsuspension of the hook, the boom can easily be turned on the mast orcentral standard and if the load is to be moved to any point along thelength of the boom, it is only necessary to apply a light force orpressure against the load in the direction in which it is desired tomove the same. As the heavy base 1 and the counter-weight 22 balance allparts of the boom and even the load thereon it Willbe seen that noanchoring of the base nor of any parts or guying of the mast or standardis required thus affording the possibility of operating with this cranein a confined space and permitting of readily shifting the crane so asto bring it into most suitable position for performing its Worlr.

Having described our invention what we claim as newand desire to secureby Letters Patent is 1. 1n a crane, the combination with a supportingframe, of a center plate at its upper end, which center plate has anannular rib, a housing surrounding said center plate and having aninternal annular groove, horizontal rollers contained in said housingand running on said rib of the center plate, and a boom secured to saidhousing, substantially as set forth.

2. In a crane, the`combination with a supporting frame, of a centerplate secured in the top of the frame and having an external annularrib, a housing loosely surrounding the center plate, horizontal frictionrollers in said housing and resting against the rib, a set of verticalrollers between the center plate and the rotative housing, and a boomsecured on the housing, substantially as set forth.

3. In a crane, the combination with a supporting frame, of a centerplate secured on the same and provided with an external annular ribhaving inclined top and bottom faces, a housing loosely surrounding thecenter plate and having a beveled internal annular Arecess provided withan inclined top and bottom, friction rollers in the shape of a truncatedcone resting respectively between the upper surface of the rib and thetop of the recess and the under surface of the rib and the bottom of therecess and a boom securedto said housing, substantially as set forth.

4. In a crane, the combination with an upright frame, of a center platesecured on the upper end of the same, a housing mounted rotatively onsaid center plate, and provided with upwardly projecting lugs, beamsforming the boom resting on the Vhousing and riveted to said lugs,substantially as set forth.

5. In a crane, the combination with a base, with uprights secured to thebase, a center plate connecting the vuprights at their upper ends, of ahousing loosely surrounding the center plate and a boom attached to saidhousing, substantially as set forth.

6. ln a crane, the combination with a standard, of a boom mounted toturn'on the same, a truss frame on the boom, a truss rod having its endsconnected with the end of the boom, and passing over said truss frame,and an eye secured on the upper end of the truss frame, substantially asset forth.

7. 1n a crane, the combination with a standard, of a center plate on theupper end of the same, a housing loosely surrounding the center plate,two eye beams bolted to the center plate and forming a boom, a trussframe bolted to the inner sides of the eye beams above the housing, anupwardly extending bracket riveted to the inner sides of the eyebeams atone end of the boom, a truss rod secured to said bracket, passing overthe truss frame and secured to the opposite end of the boom, a sheavepvoted in the truss frame, a carriage on the boom,

sheaves on the carriage, a hoisting cable secured to said bracket andpassed over the of Mercer and State of New JerseyT this 1.0

Signed at the city of Trenton in the county sheaves on the carriage andover the sheave twenty-Erst day of June A. D. 1907.

on the truss frame, a Winding drum with which the cable s connected, anda hoisting hook suspended from that part of the chain between the tWosheaves on the carriage, substantially as set forth.

HOWARD H. MAXFIELD. G. CLINTON GARDNER, JR. Witnesses:

SCOTT SCAMMELL, v JOHN H. WooLvERToN.

